Escapement



u 21, 1945. M RHODES 2,383,418

ESCAPEMENT Original Filed Dec. 12, 1940 ij Flea Patented Aug. 21, 1945 ESCAPEMENT Marcus H. Rhodes, Hartford, Conn, assignor to M. H. Rhodes, ration of Delaware Inc., Hartford, Conn, a corpo- Original application December 12, 1940, Serial No. 369,693, now Patent No. 2,363,993, dated November- 28, 1944. Divided and this application April 19, 1941, Serial No. 389,312

2 Claims. (01. 58117) 'Thi invention relates to escapements, and with regard to certain more specific features, to impulse escapments. 1 1

. The invention is an improvement upon the construction disclosed in Franz United States Patent 1,934,611, dated November 7,1933.

This application is a division of my United States application Serial No. 369,693, filed Decemer 12, 1940, for Escapement, eventuated as Patent No. 2,363,993,dated.November 28, 194:4.

Among the several objects of the invention may be noted the provision of an esoapement for controlling gear trains and the like in which the. advantage is obtained of a radius of application of the impulse, which is greater during at least part of the time of the impulse, than the braking radius of the esoapement; the provision of an esoapement of the class described which is independent in operation of the character of the finish on the esoapement teeth and in which a quiet and smoothly acting recessive wiping contact is attained; the provision of an esoapement of the class described in' which hooking action is avoided between a formed unsymmetrically and sloping in the direction of their advance; and the provision of escapement apparatus which is characterized by quietness and a large angle of action staff. Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly. comprises the elements and combinationsof elements, features of construction, and arrangements of parts which will be exemplifiedin the structures hereinafter described, and the scope of the application of which Will be indicated in the following claims.

In the accompanying drawing, in which are illustrated several of ments of the invention,

Fig. 1 is a vertical section taken on line l-l of Fig. 2, showing an esoapement wheel, a balance staff, and in part a hair spring;

Fig. 2 is a vertical section taken on line 2-2 of Fig. 1;

Fig. 3 is an enlarged fragmentary view of the esoapement wheel and balance stall in a position succeeding that of Fig. 1;

Fig. 4 is a view similar to Fig. 3 showing a succeeding position; and,

Fig. 5 is a viewsimilar to Fig. 4 showing another succeeding position.

Similar reference characters indicate corresponding parts throughout the several views of the drawing.

of the balance 4 pallet and esoapement teeth, the latter, for purposes which will appear, being various possible embodi In the construction of the Franz patent there is a driving radius onthe balance staff which is greater at all times than the braking radius. It

is useful so long as the machine work is good on the teeth of the esoapement wheel, and as long as the driving pin is used in conjunction with an esoapement tooth of a suitable angle to cam the pin, instead of hooking in behind the pin as would be the case if a ratchet type of driving tooth were used. Also, if burrs occur at or near the ends of the teeth, it sometimes happens that these act as hooks behind the driven pin, thus holding the pin and interfering with proper operation.

The present invention avoids this interference Without the necessityfor removing burrs during the manufacture of the esoapement wheel and also obtains improved results. This is done by providing a pallet connection between what may be'consiclered the pin portion (in the patent) with the grooved portion on the balance staff, so that the esoapement teeth function on this pallet, but without the disadvantages of ordinary pallets.

Referring now more particularly to Figs. 1 and 2 herein, numerals l and 3 indicate spaced frame plates for supporting the usual gear train which the present esoapement controls. The last gear or pinion of the train is shown at 5 and it is this gear that drives the esoapement.

The gear 5 is attached to a shaft 7 to which also is fastened a toothed esoapement wheel 9 which, through the action of the gear train on the gear 5, is biased to-rotate inthe direction shown by the arrows. Solid arrows indicate rotary conditions and dotted arrows indicate a mere rotary bias without movement.

Numeral l l indicates the balance staff carrying a balance member I 3. l A vibratory hair spring 5 is also attached at one end to the balance staff I I and anchored at the other end to the frame, as indicated at wedge"l1.

The center line of the balance staff II is only slightly beyond the ends of the teeth [9 of the esoapement wheel 9, so that, in the absence of any notch in the staff, the ends of the teeth [9 are biased against the shaft. The teeth l9 are substantially in the same plane. 1

To provide for successive passage of the teeth I 9, the shaft balance staff I I is notched at 2!. To provide for driving the staff H from the esoapement wheel 9, a radial plate 23 is attached to the stall l l and extends outward through the planeof the notch. For convenience, this plate may be referred to as a pallet. It extends beyond the surface (of the staff II, and thus beyond the notch 21.

The parts are related in Fig.3 to show the toothed escapement wheel 9 just released and about to move freely to the right under bias from the spring which drives the gear train meshed with the pinion gear 5. At this time the staff II with the pallet 23 is moving clockwise, under action of spring l5. The pallet passes to the left through the respective space 25 between teeth IS. The tooth [9A having just escaped, the tooth I9B is proceeding to pallet-pushing position.

In Fig. 4 the pallet 23 is shown as having proceeded clockwise to be met by the oncoming tooth I9B, which stops the clockwise rotation of the staff II and again forces it counterclockwise to the position shown in Fig. 5,.the tooth ISB meanwhile escaping from underthe pallet. The oncoming tooth I90 then strikes the braking surstaff II. The staff ll then continues to move counterclockwise while winding up the hair spring l5 and under the friction braking action of tooth [9C until the final stationary position of the staff ll of Fig, 1 is reached, wherein the hair spring I5 is wound up. Thereafter the hair spring vibrates back and forces the staff I l clockwise to release the tooth I9C into the notch 2|, to be met subsequently by the pallet 23 to repeat the cycle.

It will be noted that, since the pallet 23 extends beyond the surface of the staff II, the accelerating push on the staff is delivered at a radius which for at least a part of the time is greater than the braking radius at contact between a tooth. and the braking surface 2 of the staff ll.

It will also be noted in the drawing that the teeth l9 are unsymmetrical and in effect slope in the direction of their advance, that is, they are ratched shaped. Stated otherwise they are forwardly hook shaped with a forward undercut. This is the general shape that, even if flat on the front face,'would develop a hooking action behind the pin in the case of said Franz patent, and which isavoided by the radial pallet construction herein. The'ratchet-shaped teeth are desired in many cases, though not all cases, because they deliver an initial power impulse'which is superior to a, non-ratchet type of tooth. This is because the impulse is to be delivered straight ahead at a line more or less perpendicular to the center line between the shafts! and II.

' face 2 constituted by the cylindrical back of the The staff I I has the notch 2| cut into it per se, without introducing an extra fitting. This produces a braking surface of practical minimum radius, which in some cases is desirable. At the same time, the radial pallet extends so that there is a substantial intersection wlththe path of the coplanar teeth is.

In View of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

I claim-:

'1. An escapement mechanism comprising an escapement wheel having escapement teeth, all parts of which are substantially in a plane, said teeth having at least their forward faces sloping from their bottoms to their tops in the direction of their normal advance, an oscillating 'balance staff having a braking surface associated with said staff and anotch permitting escapement of said teeth successively and terminating the braking surface, and a pallet having a continuous pallet face extending from said notch to a point outside of the radius of the braking surface, said pallet face being adapted to be engaged by said teeth as they pass successively through said notch, said pallet face having a surface engaged by the teeth without a hooking action.

2. An escapement mechanism comprising an escapement wheel having escapement teeth, all parts of which are substantially in a plane, each tooth being shaped with a forward undercut portion, an oscillating balance staff having a braking surface associated with saidstaff and a notch permitting escapement of said teeth successively in the direction of their undercuts and terminating the braking surface, and apallet having a continuous pallet face extending from said notch to a point outside of the radius of the braking surface, said pallet face being adapted to be engaged by the undercut portions of said teeth as they pass successively through said notch, the extension of the-pallet and'the undercut portions of the escapement teeth being such that during escape action of a tooth, the end portion ofthe pallet is first engaged at a relatively large radius on the pallet by the undercut portion of the tooth and then by the end of the tooth at a smaller radius on the pallet, the face of the pallet being of a continuous form such that hooking is avoided between the escapement teeth and the pallet.

MARCUS H. RHODES. 

